Fig. 4: FISH visualization of condensin domains in the cnd1-K658E mutant and Pmc4-depleted cells.

a Positions of FISH probes. Probes #1 and #2 span adjacent condensin domains (dotted lines), while probes #2 and #3 are positioned within a single domain. The genomic regions targeted by these probes are consistently separated by 110 kb for both inter-domain and intra-domain FISH probes. An enlarged difference map of the 1.9 Mb region on chromosome I, comparing Cnd1-depleted and Cnd1-WT cells, is shown to represent condensin domains; experimental details are provided in Supplementary Fig. 3. b Quantification of distances between inter-domain or intra-domain FISH probes in interphase and mitotic cells of the wild-type (cnd1-WT) and cnd1-K658E mutant (cnd1-K658E) strains. Representative FISH-IF images were shown below, displaying two loci (red and green) and spindle microtubules (blue; mitotic marker). c Quantification of distances between inter-domain or intra-domain FISH probes in interphase and mitotic cells expressing Pmc4 from a plasmid (Pmc4 WT) or lacking plasmid-derived Pmc4 (Pmc4 depletion). Endogenous Pmc4 was removed by the AID system. d Schematic representations of mitotic condensin domains under the indicated conditions. Green and red dots indicate the schematic positions of genomic regions visualized by FISH probes (#1, #2, and #3). In wild-type cells, two adjacent condensin domains are formed during mitosis. In mitotic cells of the cnd1-K658E mutant, these domains are impaired and occupy larger areas, leading to increased intra-domain distances compared to wild-type cells. In mitotic cells depleted of Pmc4, the distances between the two domains are shortened, suggesting a disruption of domain boundary formation. The central bar represents the median, with the boxes indicating the upper and lower quartiles. The whiskers extend to data points within 1.5× the interquartile range from the box. P-values were calculated by two-sided Mann–Whitney U test. Source data for (b, c) are provided as a Source Data file.